Pre-terminated optical fiber cabling systems are used to dramatically streamline the process of deploying an optical networking infrastructure in the premises environment, particularly in data center applications. Such systems significantly reduce installation time and cost. Pre-terminated modular components of the system are simple to configure and can be installed, connected and operational in a fraction of the time when compared to using conventional, field-terminated methods. Commonly used pre-terminated modular components include jumper cables (“jumpers”), trunk cables, breakout modules, and breakout harnesses.
One important aspect of designing, manufacturing and deploying components in a pre-terminated and modular optical cabling system (or network) is ensuring that the duplexed transmitters and receivers connection locations on one end of the optical path defined by the system are in optical communication with select receive and transmit connection locations at the opposite end of the optical path. Management of how the transmit and receive connections locations are interconnected is commonly known as “polarity management.”
Most modular optical cabling systems in commercial use are based upon cable assemblies having 12-fiber MPO-style connectors. In particular, these systems utilize trunk cables having fiber counts in multiples of 12 and that are furcated into one or more 12-fiber legs, with each leg terminated with a 12-fiber MPO-style connector. These trunk cables are placed into cable pathways to span the distance between various equipment locations, patching locations (cross-connects and interconnects) and other network access points.
To establish connectivity with duplex transceiver ports commonly used on active equipment, these trunk cables must be transitioned to duplexed single-fiber connectors or 2-fiber connectors. This is accomplished by mating the trunk's 12-fiber MPO connectors to breakout harnesses or breakout modules having 12-fiber MPO connectors on one end and either (a) 2-fiber connectors such as MT-RJ® connectors, or more commonly (b) duplexed single fiber connectors such as SC or LC connectors that are duplexed together with a duplexing adapters, clips or boots. These breakout assemblies are therefore sometimes collectively referred to as “transition assemblies” or “fan-out assemblies.”
Bandwidth performance of some conventional optical fibers can be extended beyond their original performance specifications by concatenating them with engineered lengths of special optical fibers at optimal proximity to either the transmit or receive end of an optical link. Although these special fibers could be incorporated into the jumpers, there are practical considerations that make it more attractive to incorporate the special fibers into a breakout assembly, thereby extending the conventional functionality of a breakout assembly beyond that of merely transitioning from MPO connectors to duplex or 2-fiber connectors. Since a breakout assembly conventionally comprises duplexed fiber pairs terminated at one end into the same MPO connector, this means that the breakout assembly would need to comprise two different optical fibers or perhaps fibers of significantly different lengths. While it is possible to manufacture and test breakout assemblies with differing optical fibers and lengths, these requirements introduce complexities in manufacturing and testing that are undesirable and which conventional designs of breakout assemblies never anticipated.
Consequently, there is a need for a new type of breakout assembly and methods of concatenating such assemblies to form optical pathways that are capable of extending the performance of existing and future fiber installations while properly manage the polarity requirements of the cabling system while exploiting the benefits associated with factory pre-terminated modular components. Furthermore, it is desirable that these breakout assemblies be easy to manufacture and test when they contain more than one type or length of fiber.